For the formation of which compound in Ellingham diagram $$\Delta G^{\circ}$$ becomes more and more negative with increase in temperature?

Copper is extracted from copper pyrites by

Function of potassium ethyl xanthate in froth floatation process is to make the ore

Sulphide ore on roasting gives a gas $$X$$. $$X$$ reacts with $$\mathrm{Cl}_2$$ in the presence of activated charcoal to give $$Y$$. $$Y$$ is